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Preparation of a Blood Culture Pellet for Rapid Bacterial Identification and Antibiotic Susceptibility Testing
Published on: October 15, 2014
External validation of ID-BactER and Shapiro scores for predicting bacteraemia in the emergency department
Sebastián Quintero Montealegre1, Andrés Felipe Flórez Monroy2, Javier Ricardo Garzón Herazo2,3
1Department of Internal Medicine, Hospital Universitario San Ignacio, Carrera 7 No 40-62, 7th Floor, Bogotá 110231, Colombia.
Introduction:
The blood culture positivity rate in the emergency department (ED) is <20%; however, the mortality associated with Community-acquired bacteraemia (CAB) is as high as 37.8%. For this reason, several models have been developed to predict blood culture positivity for the diagnosis of CAB.
Objective:
To validate two bacteraemia prediction models in a high-complexity hospital in Colombia.
Design:
External validation study of the ID-BactER and Shapiro scores based on a consecutive cohort of patients who underwent blood culture within 48 h of ED admission.
Methods:
Scale calibration was assessed by comparing expected and observed events (calibration belt). Discriminatory ability was assessed by area under the ROC curve (AUC-ROC).
Results:
We included 1347 patients, of whom 18.85% were diagnosed with CAB. The most common focus of infection was the respiratory tract (36.23%), and the most common microorganism was Escherichia coli (52.15%). The Shapiro score underestimated the risk in all categories and its discriminatory ability was poor (AUC 0.68 CI 95% 0.64-0.73). In contrast, the ID-BactER score showed an adequate observed/expected event ratio of 1.07 (CI 0.85-1.36; p = 0.018) and adequate calibration when expected events were greater than 20%, in addition to good discriminatory ability (AUC 0.74 95% CI 0.70-0.78).
Conclusion:
The Shapiro score is not calibrated, and its discriminatory ability is poor. ID-BactER has an adequate calibration when the expected events are higher than 20%. Limiting blood culture collection to patients with an ID-BactER score ⩾4 could reduce unnecessary blood culture collection and thus health care costs.
